Prism



UFICH bl! HUUIH June 7, 1 938.

0. K. KASPEREIT PRISM Filed March 22, 1937 c vlall BYIIE.

Inventor Elttcl K- 5pereit Hy M/EWK Attnr-ne Patented June 7, 1938 UNITED STATES PATENT OFFICE 1 Claim.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to a prism.

The purpose of the invention is to provide a one-piece prism designed to deviate the line of sight through an angle of 90 in the horizontal plane and through an angle of 60 in the vetrical plane and to invert and revert the image.

A practical embodiment of the invention is illustrated in the accompanying drawing, in which,

Fig. 1 is a plan view.

Fig. 2 is a view in rear elevation.

Fig. 3 is an end view.

Referring to the drawing by characters of reference, the angles alpha are equal to 60 and the angle beta is equal to 45.

The prisms consist of a single block having parallel front and rear faces respectively 5 and 6. Only a portion of the front face is employed as an entrant face 5 and opposite this portion is a reflecting face 1 making an angle of 45 therewith. The left end portion of the prism therefor constitutes a right-angle reflecting prism whose bottom face 8 is disposed horizontally. The prism has an inclined reflecting face 9 disposed in the path of the rays reflected by the face 1 and at an angle of 60 to the vertical line of the prism as indicated by the angle of alpha in Fig. 2. The right end of the prism forms an emergent face ll! at an angle of 60 to the reflecting face 9 and perpendicular to the path of rays reflected by the face 9. The upper face ll of the prism is a plane continuous surface.

The rays of light entering the prism at the face 5 are deviated by the reflecting face 1 through an angle of 90 in the horizontal plane and are directed onto the face 9 which deviates them through an angle of 60 in the vertical plane. An inspection of the horizontal rays a, b, c, and the vertical rays a, d, e, shows that the image will appear inverted and reverted in the emergent face I0.

I claim:

A single prism for inverting and reverting an image embodying an entrant face for rays of light. a first reflecting face disposed at an angle of to the entrant face for deviating the rays of light through 90 a second reflecting face making an angle of with a plane perpendicular to the path of the rays deviated by the first reflecting face and receiving the rays of light from the first reflecting face and deviating them through an angle of 60 to the plane perpendicular to the path of the reflected rays and an emergent face making an angle of 60 with the second reflecting face.

O'ITO K. KASPEREIT. 

